Tobacco



Patented Dec. 8, 1936 PATENT OFFICE TOBACCO Raymond P. Allen, Akron, Ohio No Drawing. Application December 22, 1932, Serial No. 648,439

12 Claims.

This invention relates to a process of treating tobacco by which moisture or an aromatic substance such as menthol may be added to tobacco and be retained indefinitely until the tobacco is smoked. The process consists in homogeneously mixing with the tobacco, silica hydrogel or another strongly adsorbent material on which has been adsorbed the tobacco conditioning agent, such as moisture or menthol. Under ordinary conditions of temperature and pressure the adsorbent material, for example silica hydrogel, holds the adsorbed material tenaciously and will retain it indefinitely or until the tobacco is smoked. When the silica hydrogel is heated to the temperature of the burning tobacco, the adsorbed substance is volatilized and passes along with the smoke into the mouth of the smoker, thereby imparting the desired flavor or providing moisture which is responsible for additional flavor and smoothness. The process has the additional advantages that the adsorbent substance is tasteless and physiologically inert when heated.

It is a well recognized fact that the flavor of tobacco when smoked depends to a considerable extent on the amount of moisture present. Dry tobacco is harsh, flavorless, and irritating, while moist tobacco has a quality of smoothness, is relatively full of flavor and aroma, and is pleasant. The flavor of tobacco when smoked depends, also, to some extent on added substances, such as cassia oil, licorice, menthol, and so forth. It is recognized that the moisture which is present in tobacco and the flavors which are added are largely evanescent. For that reason in commercial practice, cigars, cigarettes, and pipe tobacco are packed after manufacture in wrappers which are more or less moisture-proof and more or less impermeable to vapors. Such means of retaining moisture and aromatic substances are, however, not satisfactory. The packages must be opened and are kept partially exposed to the air before the contents are used up. More important, under ordinary conditions of temperature, pressure and humidity, is the fact that the moisture and aromatic substance are slowly vaporized and lost through the more or less permeable packing.

On the other hand, with tobacco which has been treated by the process which I employ in this invention, moisture and aromatic substances will be effectively and indefinitely retained until the tobacco is smoked, even when the tobacco is stored under conditions of temperature, pressure and humidity which are distinctly unfavorable for the retention of moisture or volatile aromatic substances.

For example, cigarettes may be made from tobacco with which has been mixed 10 per cent. of silica hydrogel on which after activation has been adsorbed about 15 per cent. of water. If the cigarettes are stored in a dry atmosphere at a temperature of 35 to 4.5 C., for several months, it will be found at the end of that time that these cigarettes are mild, relative smooth and rela tively full of flavor and aroma, whereas cigarettes made from tobacco untreated by this process will be strong, harsh, and lacking in flavor.

It has been recognized that the addition of aromatic substances to tobacco imparts a pleasant flavor to the tobacco. In methods hitherto used the tobacco has been treated by soaking it in a suitable solution of the aromatic substance, or

the solution has been sprayed on the tobacco.

One disadvantage of such a process is that most aromatic substances which are suitable for this use have an appreciable vapor pressure at ordinary temperatures and for that reason the substance more or less rapidly vaporizes and escapes. In the process of my invention a wide variety of aromatic substances may be used and when adsorbed on a suitable adsorbent such as silica gel, exhibit a vapor pressure so extremely low at ordinary temperatures that the substances do not vaporize and escape.

For example, cigarette tobacco may be mixed. with 5 per cent. of silica gel, which after activation has been treated with an alcoholic solution of menthol, and may be made into cigarettes.

These cigarettes have a barely perceptible odor of menthol, which shows that practically none is being lost by volatilization, yet when smoked a distinct menthol flavor is experienced. The silica gel is so effective in retaining the menthol that practically none is lost even after months of storage. It is a striking fact that cigarettes so prepared retain the menthol flavor to the very end'as the cigarette is smoked, whereas with cigarettes in which the menthol has been incorporated by the ordinary spraying or soaking process, the menthol flavor is stronger during the first part of the smoke and continually decreases to the end.

This invention is not limited in application to the admixture of tobacco and a single adsorbent substance on which is adsorbed a single volatile material such as menthol. On the contrary, in carrying out the process of this invention a batch of tobacco may be mixed with one or more ad sorbent substances, on any one of which may be adsorbed both moisture and an aromatic substance or any desirable combination of volatile substances which will subsequently be vaporized when the tobacco is smoked; or two or more different volatile substances may be separately adsorbed on different adsorbents, which are then mixed with the tobacco.

The process of this invention may be carried out, also, by mixing activated silica gel or another suitable adsorbent with fresh raw tobacco which is ready to be made into cigars, cigarettes, or into pipe tobacco. The adsorbent material will thereupon adsorb moisture and flavor from the tobacco and retain this until the tobacco is smoked. This process is particularly desirable if the tobacco is to be shipped and used in a climate'which is especially humid, such as tropic or semi-tropical regions.

In the process of this invention, therefore, an adsorbent substance such as silica hydrogel may either be mixed in a dry condition with raw tobacco from which it then adsorbs moisture and aromatic substances or it may be allowed to adsorb moisture or an aromatic substance, or both, before it is mixed with the tobacco. The term adsorbent substance as used here in describing this invention therefore means a substance such as silica hydrogel which after being mixed with tobacco does contain an appreciable quantity of a volatile substance or of volatile substances which will be vaporized when the tobacco burns.

It has already been stated that among these volatile substances may be moisture, cassia oil, menthol, licorice or other substances which will be vaporized and result in an added flavor or aroma when the tobacco is smoked. These volatile substances which either directly or indirectly give added flavor to the tobacco may be conveniently termed tobacco conditioning agents. Specifically in describing this invention they may be termed adsorbed tobacco conditioning agents.

While silica hydrogel has been the only adsorbent substance so far mentioned in the description of the process of this invention, other strongly adsorbent substances may be used. For example, other siliceous substances such as kieselguhr, fullers earth, certain clays and siliceous earth, when properly activated, or carbonaceous material such as active charcoal, or aluminiferous substances such as activated bauxite and alumina hydrogel, or other strongly adsorbent substances such as properly prepared ferric oxide may be used in place of the silica hydrogel as adsorbing agents for moisture or aromatic substances. An advantage of these adsorbent materials which are used in this process is that they are tasteless and odorless, even when heated. From this standpoint, therefore, they serve as ideal carriers'of flavors, while they themselves remain physiologically inert.

In order to have the adsorbent material most effective, it is desirable that it be activated before use by the most approved method, as will be understood by those who are skilled in the use of such materials. For example, silica gel may be activated by heating to a temperature of 300 C. for two hours, whereupon it is capable of adsorbing approximately 20 per cent., by weight, of moisture.

In carrying out this process it has been found most desirable to have the silica gel finely divided, that is, of the order of size of material which will pass a standard sieve with two hundred meshes to the inch, but the invention is not limited to the use of an adsorbent material of this dimension.

No special precautions are ordinarily necessary in order to make the silica gel or other adsorbent material adhere to the tobacco, but the process may in some cases be improved by using a small amount of a physiologically inert adhesive such as a dilute solution of water glass.

I claim:

1. A substantially homogeneous mixture of tobacco and a highly activated adsorbent substance on which is adsorbeda volatile flavoring agent.

2. A substantially homogeneous mixture of tobacco and a highly activated adsorbent substance on whichis adsorbed menthol.

3. A substantially homogeneous mixture of tobacco and a highly activated siliceous hydrogel on which is adsorbed a volatile flavoring agent.

4. A substantially homogeneous mixture of tobacco and a highly activated alumina hydrogel -on which is adsorbed a volatile flavoring agent.

5. A substantially homogeneous mixture of tobacco and activated carbon on which is adsorbed a volatile flavoring agent. 7 V

6. A substantially homogeneous mixture of tobacco and activated carbon on which is'adsorbed menthol.

'7. A substantially homogeneous mixture of tobacco and a highly activated adsorbent substance on which is adsorbed moisture and an aromatic substance.

8. A substantially homogeneous mixture of tobacco and more than one highly activated adsorbent substance on which are adsorbed one or more volatile flavoring substances.

9. A cigarette containing tobacco admixed with a highly activated adsorbent substance on which is adsorbed moisture and an aromatic substance.

10. A cigarette containing tobacco admixed with one or more'highly activated adsorbent substances on whichare adsorbed more than one volatile flavoring substance.

11. A cigarette containing tobacco admixed with a highly activated alumina 'hydrogel on which is adsorbed a volatile flavoring agent.

12. A cigarette containing tobacco admixed with activated carbon on which is adsorbed men thol,

RAYMOND P. ALLEN. 

